Submarine signal



July 26, 1966 w. H. REAMS SUBMARINE SIGNAL Filed Sept. 29, 1964 IFHG.

William H. Reams INVENTOR. WW BY ATTORNEY.

United States Patent 3,262,387 SUBMARINE SIGNAL William H. Reams, Adelphi, Md., assignor to the United States of America as represented by the Secretary of the Navy Filed Sept. 29, 1964, Ser. No. 490,287 4 Claims. (Cl. 102-16) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to the art of signaling. More particularly, the invention relates to a conditionresponsive firing system for a buoyant submarine signal and to a signal embodying such a firing system.

Submarine signaling systems are known in which a buoyant body is released to rise to the surface and to initiate a pyrotechnic display upon reaching the surface. In the past, the means for initiating the pyrotechnic display has been a combination of a hydrostatic switch and a delay timer. The hydrostatic switch was adjusted to start the timer when the signal reached a predetermined depth below the surface of the water, the timer then initiating the pyrotechnic display after a time interval dependent upon the depth setting of the hydrostatic switch and the time required for the signal to reach the surface from the depth, calculated from knowledge as to its average velocity. This system has several disadvantages, principal among which is its lack of accuracy. The difficulty lies mainly with the hydrostatic switch, since it is diflicult to make such a switch to be accurate within plus or minus feet. This is especially so when it is also desired to keep the cost of components at a minimum. Accordingly, in some instances, the prior art system will initiate too soon and the pyrotechnic display will be fired before the signal has had time to reach the surface of the water, resulting in a failure of the display. If the hydrostatic switch fails to close until after the signal has passed the predetermined depth, the timer will allow the signal to remain at the surface for a time before initiating the display. The signal will then be acted upon by waves and surface turbulence, and consequently, may not be in a vertical position at the time of initiation of the display. Here, at least a partial failure of the system results.

It is therefore an object of the present invention to provide a condition responsive switching system which will initiate an event in a buoyant vehicle just as it reaches the surface of the-water.

It is a further object of the invention to provide a system for reliably firing a submarine signaling device just as it reaches the surface of the water.

Still another object of the invention is to provide a submarine signaling device which will be reliable in operation and which employs a minimum number of parts.

The objects of the invention are accomplished by the provision, in combination with a hydrostatic arming switch, of a dynamic pressure sensing switch communicating with the water surrounding the signal. Switches responsive to dynamic pressure or velocity head resulting from the velocity of the body through the water are generally known, an example of such a switch being the fluid pressure differential switch of Patent No. 2,961,506 issued to James M. Kendall on November 22, 1960, employed in a torpedo exploder mechanism. Such a switch can sense directly the drop in velocity of a signal as it leaves the surface of the water vertically, as well as the change in fiuid density at the air-water interface. As indicated above, a hydrostatic switch is also used in the present combination as an arming switch to keep the fir- Patented July 26, 1966 ing circuit open while the vehicle is submerged and at rest.

Other objects and advantages of the invention will be apparent from a consideration of the following detaileddescription, when read in conjunction with the accompanying drawings wherein:

FIG. 1 is an illustration of a submarine signaling de vice of the type contemplated by the present invention;

FIG. 2 is a cross-sectionalshowing of a dynamic pressure switch which may be employed in the present system; and

FIG. 3 is an electrical circuit diagram of the system.

Referring now to FIG. 1, there is shown a submarine signaling device embodying the present invention. It will be understood, of course, that the vehicle need not be a submarine signal, but may be any vehicle which is intended to rise to or near the surface of the water to perform its intended function. The buoyant body could be, for example, a mine which, prior to its intended detonation, is held in a submerged position and released to rise to the surface and explode there.

The vehicle shown in FIG. 1 has an elongated tubular body 10, a head end 11 and a tail section 12. A port 13 is provided in body 10 for communication with a hydrostatic switch of ordinary construction contained within the body of the vehicle. Probes 14 and 16, the structure and function of which will be later described, extend outwardly from the body of the vehicle 10 into the zone of the slip-stream of the fluid through which the vehicle passes. body 10 contains a pyrotechnic display system consisting of a pyrotechnic package and means for projecting it into the air. The details of the pyrotechnic display are not necessary to an understanding of the present invention and therefore need not be described further.

FIG. 2 illustrates the dynamic pressure sensing switch which is preferably employed in the present invention. This switch designated S comprises a housing 17, which in the illustrated embodiment is a continuation of the main body 10 of the signaling device. Housing 17 has a bulkhead 18 near one end thereof and a threaded opening 19 at the other end. A stepped-down chamber is contained within housing 17 and is defined by cylindrical walls 21 and 22 and shoulder 23. Shoulder 23 cooperates with the end of cylindrical wall 24 of a cup-shaped element 25 to clamp the free edge of a piston and diaphragm assembly 26. Cup-shaped element 25 is secured within housing 17 in clamping relation with the piston and diaphragm assembly 26 by rneans of a threaded plug 27 having a bearing portion 28 thereon acting against the end face 29 of the cup-shaped element 25. A hexagonal projection 30 is provided on threaded plug 27 adapted to be engaged by a wrench for fastening plug 27 in place,

Piston and diaphragm assembly 26 consists of 21 diaphragm 31 made of rubberor other like material and hav ing an enlarged rim portion 32 thereon which is disposed in a suitable groove in the end face of cylindrical wall 24 of cup-shaped element 25. The central portion of diaphragm 31 is clamped between two piston elements 33 and 34 secured together by means of a suitable fastener 36. Piston element 33 is cup-shaped as shown to provide an exterior surface of substantial length for cooperation with the rolled portion 37 of diaphragm 31 as the entire assembly 26 moves axially in the chamber. Projecting from piston element 34 is a shaft 38 which extends through a bore 39 in bulkhead 18 to act as the movable element of the electric switch means to be later described. The entire assembly 26 is biased to the right in FIG. 2 by a spring 40 acting between element 25 and piston element 33. Suitable bosses 41 and 42 are provided on cup-shaped elements 25 and 33 respectively to support spring 40 in known manner.

As in prior submarine signaling devices the Fluid communication is obtained to the chamber a at the right side. of the piston and. diaphragm assembly 26 in FIG. 2 by a tapped bore 43 and tubular probe 14 threadably secured in tapped bore 43. Probe 14 is L- shaped to provide a flow-path facing'forward of the vehicle or directly into the relatively flowing fluid as the body moves therethrough. Fluid communication is also established to chamber 20b at the opposite side of the assembly 26. bymeans of probe 16 similar to probe 14 secured in a tapped bore 47 in housing 17. A bore 48 in the wall 24 of cup-shaped element is arranged to be coaxial with tapped. bore 47 when the device is assembled to complete the fluid connection. As shown probe 16 has its Opening directed oppositely to the direction of the fluid flow. It should be here understood'that probe 16 is not essential to the operation of the. device. but, in providing a lower-thanambient pressure on the rear of the diaphragm, aids in the operationof. the switch.

As mentioned above, shaft 38 constitutes one portion of the actual. contact assembly of the present switch. The other contact is shown in FIG. 2 at 49. Contact 49 is preferably carried for axial adjustment with respect to housing. 17 by a shaft, 50 threadedly engaged in a suitable contactv support. 51. Contact support 51 has an annular base 52 thereon which is secured, by suitable fasteners 53,.to bulkhead 18 of body 17. A suitable fluid seal such as an O-ring 54 is also secured between these elements. A fluid seal betweenshaft 50 and contact support 51 is accomplished by means of an O-ring 56.

It will be apparent that in the embodiment shown, one side of the switch is constituted by the body thereof, electrical communication being from shaft 38, through fastener 36 to piston element 33, through spring to the cupshaped body 25' to the body 17'. It is therefore necessary to insulate the contact 49 from the body of the switch in order to accomplish the switching function. For this purpose the contact 49 is held in the end of threaded shaft 50 by means of an insulating body 57'. The electrical lead to contact 49' extends. axially through element 50 in an axial bore 58 therein and is provided with suitable insulation 59.

In completing the description of the structure of the switch, it is pointed out that the bulkhead 18 is also provided with communicating bores 60 and 61 communicating between the chamber 20a the area surrounding the switch contacts themselves. The function of these through passages is to equalize the fluid pressure on either side of bulkhead 18, to maximize. the area of the diaphragm assembly acted upon by the dynamic pressure. The presence of sea water between the contact elements 38 and 49 is not critical to the operation of the device, since the voltage in the circuit is maintained low at all times, and conduction through the sea water is negligible.

The electrical circuit of the present system is quite simple, consisting of a single loop having the switch S a conventional hydrostatic switch in series therewith, shown at S a suitable source of electrical energy such as a battery 62 and the :means for initiating the pyrotechnic display or other operation which may be, for example, an explosive squib, shown at 63. The mechanical operating means for switches S and S are diagrammatically shown in this figure.

The operation of the system will now be described. Consider first the condition where the vehicle is at rest, submerged some distance below the surface of the water. This is the state in which the instrument will exist until it is desired to release it to execute the signaling operation. Under these conditions, switch S is in the closed condition because of the lack of fluid flow past the vehicle and the consequent lack of pressure acting on the diaphragm assembly 26. Switch S however, is maintained in the open condition by the hydrostatic pressure of the water surrounding the vehicle. Thus the electrical circuit is open.

After the signal has been released and begins its rise through the water, the pressure will gradually build in chamber 20a as the velocity increases, the pressure increasing to some level above ambient hydrostatic, proportional to the velocity of the body and the density of the fluid. If probe 46, is used, the pressure in chamber 20b will decrease below ambient because of the arrangement of probe 46 away from the direction of fiow. The pressure acting on assembly 26 moves the piston and diaphragm assembly to the left in FIG. 2, and consequently opens switch S When the vehicle reaches the depth at which the hydrostatic switch S has been set,

switch S will close, arming the signal and enabling switch S to fire the squib 63 just as the signal reaches the surface of the water. As the vehicle passes the air-water interface, its buoyancy decreases, of course, and it rapidly slows down. If conditions are such that the vehicles forward motion stops prior to the time that the probes themselves clear the air-water interface, switch S responds to the drop in velocity to initiate the display. If the probes pass the interface, switch S will respond to either the drop in velocity or the sudden charge in density or both.

Thus it is apparent that a system for firing a submarine signal has been described which successfully meets the objects of the invention as set forth above. The system is highly reliable in that it is sensitive to the interface between the air and the Water and responds quickly when that interface is reached. In this manner, it cannot respond prior to reaching the surface as did prior systems on occasion; and, in firing just as it reaches the surface, it is not subjected to the action of surface turbulence for any period of time after reaching the surface and prior to initiation of the display. Moreover, these results are accomplished in a simple and eflicient manner.

It will be understood that the foregoing description is illustrative only and that within the scope of the appended claims the invention may be practiced otherwise than as here specifically described.

VJhat is claimed is:

1. In a vehicle adapted to rise through the water and cross an air-water interface, said vehicle having electroresponsive means therein for initiating an event, an improved arming and firing system for said vehicle comprising switch means for connecting a source of electrical energy to said electroresponsive means, said switch means comprising an arming switch responsive to the hydrostatic pressure'of the fluid surrounding said vehicle and adapted to be open when said vehicle is below a predetermined depth and closed at shallower depths and a firing switch connected in series with said arming switch and responsive to the dynamic pressure of the fluid flowing past said vehicle'to be open when said vehicle is under way and to close as said vehicle crosses said interface, said firing switch comprising a housing, having a chamber therein, a spring-biased piston and diaphragm assembly extending across said chamber, fluid conduit means extending from the space in said chamber on the side of said piston and diaphragm assembly which is opposite said spring to an orifice on the exterior of said vehicle, said orifice being directed into the flow of fluid passing said vehicle, and electric switch means responsive to the position of said piston and diaphragm assembly,

whereby, a complete circuit to said electroresponsive means is established at the instant that said vehicle crosses said interface.

2. An arming and firing system as defined in claim 1, wherein a second fluid conduit extends from the space in said chamber on the spring side of said piston and diaphragm assembly to a second orifice at the exterior of said vehicle, said second orifice being directed away from the flow of fluid past said vehicle.

3. In a buoyant submarine signal adapted to rise to the surface of a fluid and fire a pyrotechnic display into the air, an improved arming and firing system for said signal comprising an arming switch responsive to the hydrostatic pressure of the fluid to be open when said signal is below a predetermined depth,

a firing switch responsive to the flow of fluid past said signal to be closed when said signal is at rest and open when it is underway;

said firing switch comprising,

a housing, having a chamber therein,

a diaphragm assembly extending across said chamber,

fluid conduit means extending from a space in said chamber on one side of said diaphragm assembly to an orifice on the exterior of said signal, said orifice being directed into the flow of fluid passing said vehicle, and

electrical switch means responsive to the position of said diaphragm assembly,

whereby said pyrotechnic display is fired upon the arrival of said signal at the surface of the fluid.

4. An arming and firing system as defined in claim 3, wherein a second fluid conduit extends from a space in said chamber on the other side of said diaphragm assembly to a second orifice at the exterior of said vehicle, said second orifice being directed away from the flow of fluid past said vehicle.

References Cited by the Examiner BENJAMIN A. BORCHELT, Primary Examiner. V. R. PENDEGRASS, Assistant Examiner. 

1. IN A VEHICLE ADAPTED TO RISE THROUGH THE WATER AND CROSS AN AIR-WATER INTERFACE, SAID VEHICLE HAVING ELECTRORESPONSIVE MEANS THEREIN FOR INITIATING AN EVENT, AN IMPROVED ARMING AND FIRING SYSTEM FOR SAID VEHICLE COMPRISING SWITCH MEANS FOR CONNECTING A SOURCE OF ELECTRICAL ENERGY TO SAID ELECTRORESPONSIVE MEANS, SAID SWITCH MEANS COMPRISING AN ARMING SWITCH RESPONSIVE TO THE HYDROSTATIC PRESSURE OF THE FLUID SURROUNDING SAID VEHICLE AND ADAPTED TO BE OPEN WHEN SAID VEHICLE IS BELOW A PREDETERMINED DEPTH AND CLOSED AT SHALLOWER DEPTHS AND A FIRING SWITCH CONNECTED IN SERIES WITH SAID ARMING SWITCH AND RESPONSIVE TO THE DYNAMIC PRESSURE OF THE FLUID FLOWING PAST SAID VEHICLE TO BE OPEN WHEN SAID VEHICLE IS UNDER WAY AND TO CLOSE AS SAID VEHICLE CROSSES SAID INTERFACE, SAID FIRING SWITCH COMPRISING A HOUSING, HAVING A CHAMBER THEREIN, A SPRING-BIASED PISTON AND DIAPHRAGM ASSEMBLY EXTENDING ACROSS SAID CHAMBER, FLUID CONDUIT MEANS EXTENDING FROM THE SPACE IN SAID CHAMBER ON THE SIDE OF SAID PISTON AND DIAPHRAGM ASSEMBLY WHICH IS OPPOSITE SAID SPRING TO AN ORIFICE ON THE EXTERIOR OF SAID VEHICLE, SAID ORIFICE BEING DIRECTED INTO THE FLOW OF FLUID PASSING SAID VEHICLE, AND ELECTRIC SWITCH MEANS RESPONSIVE TO THE POSITION OF SAID PISTON AND DIAPHRAGM ASSEMBLY, WHEREBY, A COMPLETE CIRCUIT TO SAID ELECTRORESPONSIVE MEANS IS ESTABLISHED AT THE INSTANT THAT SAID VEHICLE CROSSES SAID INTERFACE. 